It's Nintendo Points. There you have it.
You get a new card, unused from Amazon.com, and it works flawlessly. Perfect if you like the older Nintendo games, like me, and want to download them; many of the WiiWare titles are great, too.
Buyer beware, though: NEVER pay more than $20USD, flat. Amazon.com occasionally sells these for $19.99, free shipping, so that's the ONLY time to get them here (or cheaper). Once Amazon.com sells out, it takes a while for them to replenish their stock, so that's when Marketplace sellers jump in and overcharge.
Before, even Amazon.com sold these for more than what they were worth, but that no longer seems to be the case.
If you can't find these here at their correct price, most retail stores sell them for $20USD, no activation charge or taxes. If they do add those, don't buy it. Go to another store that won't.